Are you one of the people who ignores the overwhelming body of evidence that shows how blacks are much more likely to use violence against police? Of course there is racism in the police force but I would say most of the time it is warranted.
Race is not as much of a hot topic like it is in the US. I do remember one figure from studying law - police in London are 9 times more likely to stop and search blacks than whites. I am not sure about there being evidence to suggest that attacks on officers in the UK are more likely to come from blacks, but there is certainly evidence that points to more blacks being involved in knife/gun crime.
This is based on London though, which may as well be a different country. I imagine statistics vary wildly in other places.
Armed response only deals with armed people/bomb threats. Police will use tasers, but it is frowned upon by the public because shit like this always seems to happen.
If someone is causing shit in a public area in London you will be taken down immediately. Met police don't fuck around.